Do corporate bond spreads reflect fear of debt deflation? Most corporate bonds have fixed nominal face values, so unexpectedly low inflation raises firms' real debt burdens and increases default risk. The first chapter develops a real business cycle model with time-varying inflation risk and optimal, but infrequent, capital structure choice. In this model, more volatile or more procyclical inflation lead to quantitatively important credit spread increases. This is true even with inflation volatility as moderate as that in developed economies since 1970. Intuitively, this result obtains because inflation persistence generates large uncertainty about the price level at long maturities and because firms cannot adjust their capital structure immediately. We find strong empirical support for our model predictions in a panel of six developed economies. Both inflation volatility and the inflation-stock return correlation have varied substantially over time and across countries. They jointly explain as much variation in credit spreads as do equity volatility and the dividend-price ratio. Credit spreads rise by 15 basis points if either inflation volatility or the inflation-stock return correlation increases by one standard deviation. Firms counteract higher debt financing costs by adjusting their capital structure in times of higher inflation uncertainty. The second chapter empirically decomposes excess return predictability in inflation-indexed and nominal government bonds into liquidity, market segmentation, real interest rate risk and inflation risk. This chapter finds evidence for time-varying liquidity premia in Treasury Inflation Protected Securities (TIPS) and for time-varying liquidity premia in TIPS and for time-varying inflation risk premia in nominal bonds. The third chapter develops a pre-test for weak instruments in linear instrumental variable regression that is robust to heteroskedasticity and autocorrelation. Our test statistic is a scaled version of the regular first-stage F statistic. The critical values depend on the long-run variance-covariance matrix of the first stage. We apply our pre-test to the instrumental variable estimation of the Elasticity of Intertemporal Substitution and find that instruments previously considered not to be weak do not exceed our threshold.